The present invention relates to a circuit translator, and particularly to an apparatus for automatically translating logic circuits that are adapted to realizing the circuits having the same functions using devices of different technologies to automatically carry out the designing of semiconductors.
Analog-digital hybrid circuits have now been widely used, the analog circuitry being constituted by an IIL (integrated injection logic) or a TTL (transistor logic) and the digital circuitry being usually constituted by a CMOS circuit. The CMOS circuit, however, must be translated into an IIL circuit or a TTL circuit. This translation has heretofore been performed by human hand involving, however, a number of steps to carry out the design. In addition to the CMOS-IIL translation, furthermore, there are a TTL-CMOS translation, a TTL-ECL translation and like translations. Therefore, it has been desired to provide a method which is capable of automatically carrying out these translations.
A conventional method of automatically translating the circuit consists of detecting a part that is in agreement with an input pattern (pattern expressed by a connecting relation among the elements) defined in advance from an original circuit, i.e., from a circuit to be translated, and replacing this part by a corresponding output pattern according to conditions such as the number of fan outs of the output terminals (see, for example, Japanese Patent Application No. 82400/1985 which is a prior application filed by the inventors of the present invention and Appropriation Design Support Systems (1), (2), (3) using Knowledge Base by Kakimoto et al., Lectures in the 30TH National Convention of the Association of Information Processing, pp. 1923-1928, 1985). According to the above-mentioned method in which a plurality of output patterns are corresponded to each of the input patterns, however, the rules are necessary in a number equal to the number of the output patterns. Therefore, increased number of translation rules are necessary for all of the input patterns, and increased number of steps are required to prepare knowledge base (i.e., to prepare translation rules), presenting disadvantage with regard to efficiency and easiness for preparing the translation rules.